The use of hydrogels for the manufacture of biomedical devices is known. Hydrogels that are copolymers of siloxane prepolymers and hydrophilic monomers offer certain advantages in comparison with conventional hydrogels. However, it is difficult to produce optically transparent, homogeneous hydrogels from these prepolymers and monomers making the use of the hydrogels limited.
Known methods for making homogeneous hydrogels from siloxane prepolymers include using diluents to compatabilize the siloxane with the hydrophilic monomer and using siloxanes into which hydrophilic groups are incorporated. However, the use of diluents is disadvantageous because of their volatility and their use may result in polymers of inferior quality. Incorporation of hydrophilic groups is disadvantageous in that it requires the use of complicated syntheses and the resulting polymer may not be optically transparent. Therefore, a need exists for a method of polymerizing siloxane prepolymers and hydrophilic monomers that overcome these disadvantages.